Method and apparatus for wet-type desulphurisation of exhaust gases using a solid de-sulphurising agent

摘要

Exhaust combustion gas is brought into contact with an absorbing liquid to absorb sulphur oxide, limestone particles having larger diameters are selectively left in a neutralising zone where the absorbing liquid is neutralized and the absorbing liquid containing water and gypsum are selectively drained from the neutralising zone to be brought into contact with the exhaust gas again; at that time the absorbing liquid that is brought into contact with the exhaust gas contains water as a main constituent so that there is the possibility of large decrease of desulphurising performance due to a variation in the load of the boiler etc and more than one item can be selected for detection e.g. pH of the neutralising liquid, S content, flow rates of exhaust gases, inlet and outlet SO 2 concentrations, so as to regulate more than one item e.g. flow rate of the absorbing liquid, stirring velocity of the solid desulphurising agent in the neutralisation zone, and thus control the outlet SO 2 concentration.